From the turn of the century and onwards centrifugal separators have normally not been designed in the manner described. Instead, the inlet of the separation chamber has been situated at the end of the separation chamber, towards which the base portions of the separation discs face. A conventional centrifugal separator of this kind is shown e.g. in U.S Pat. No. 3,986,663. However, even centrifugal separators of the latter kind have a rotor with outlets for the two separated liquids situated at one and the same axial end of the rotor. This has several advantages. Among other things the outlet members of the rotor, which may have to be adjusted, are more easily accesible. Furthermore, use of stationary so called paring members for the discharge of the separated liquids from the rotor is facilitated.
A principle advantage of a centrifugal separator of the first kind, into which a mixture is introduced in the separation chamber at the end, towards which the apices of the separation discs face, is that a pre-separation, which takes place in the inlet passages before the mixture enters the separation chamber, can be taken advantage of to the maximum. Thus, part of the relatively heavy liquid component and possibly solids in the liquid mixture, may be separated, even as the mixture, is on its way through said inlet passages between the central inlet chamber and the inlet of the separation chamber. Relatively heavy component of the supplied mixture, separated in the inlet passages, may slide along the outer walls of the inlet passages directly out into the outermost part of the separation chamber radially outside the separation discs without being disturbed by or disturbing the rest of the mixture when this flows into the separation chamber.
In a conventional centrifugal separator, in which the liquid mixture is introduced through inlet passages at the end of the separation chamber, towards which the base portions of the separation discs face, (see e.g. U.S. Pat. No. 3,986,663), a relatively heavy component of the mixture, separated in the inlet passages, is forced to cross the flow of the rest of the mixture as the latter enters the separation chamber. This is a consequence of the fact that the inlet passages have an inclination relative to the rotor axis just about the same as that of the conical separation discs. Thereby, the result of the pre-separation in the inlet passages is spoiled wholly or partly. This undesired effect of the cross flow will be greatest when the entire mixture is introduced into the separation chamber at the outer edge of the separation disc situated closest to the inlet passages.
The object of the present invention is to provide a centrifugal separator, whose rotor in the first place has the arrangement, known at least since 1904, for introducing a liquid mixture into the separation chamber and, in the second place, has both the outlets for the separated liquids available at one and the same end of the rotor. The centrifugal separator has an improved design enabling more effective separation of two liquids having different densities than a centrifugal separator of the kind shown in the above mentioned Swedish Patent No. 19666.